Effect of Dexmedetomidine on Cerebrovascular Carbon Dioxide Reactivity During Pediatric Cardiac Surgery With Cardiopulmonary Bypass

Abstract

Objective: To assess the effects of dexmedetomidine (DEX) on cerebrovascular autoregulation in children with congenital heart disease (CHD) using transcranial color-coded duplex sonography (TCCD).

Design: Randomized controlled trial.

Setting: This single-center study was conducted at a tertiary care center in Shanghai, China.

Patients: Fifty-nine children aged 0 to 6 years with CHD who underwent cardiac surgery with cardiopulmonary bypass were enrolled.

Intervention: Children were randomly assigned to receive either DEX (DEX group) or normal saline (control group) for 10 minutes following anesthetic induction. Cerebrovascular carbon dioxide reactivity (CVR-CO₂) was assessed by adjustment of lung ventilation.

Measurements and main results: Patients underwent TCCD before and after surgery. CVR-CO₂, resistance index (RI), pulsatility index (PI), mean blood flow velocity (V_mean) of the right middle cerebral artery, and regional cerebral oxygen saturation (ScrO₂) of the right frontal lobe were measured and analyzed at three distinct time points, resulting in six measurements. Hemodynamic parameters, including heart rate (HR) and mean arterial pressure (MAP), were recorded at each time point. The parameters CVR-CO₂ (p = 0.402), PI (p = 0.203), RI (p = 0.290), V_mean (p = 0.290), ScrO₂ (p = 0.426), HR (p = 0.522), and MAP (p = 0.236) were comparable between the two groups. In the control group, PI, RI, and HR significantly differed before and after surgery. In the DEX group, RI, V_mean, ScrO_2, and HR significantly differed before and after surgery.

Conclusions: A low loading dose of DEX did not compromise CVR-CO₂ in children with CHD undergoing cardiac surgery with cardiopulmonary bypass.

Keywords: carbon dioxide reactivity; cerebral autoregulation; children; congenital heart disease; transcranial color-coded duplex sonography.